Plastic closures formed from polymeric materials have met with widespread acceptance in the marketplace. Closures of this type, which have found particular applicability for carbonated and non-carbonated beverages, as well as for other applications, can be configured to provide the desired sealing performance, as well as desired tamper-indicating properties. Closures of this nature can be efficiently formed by injection molding or compression molding formation techniques.
Economical use of these types of closures has been promoted by reducing the polymeric material required for forming each closure, that is, making each closure more lightweight. However, in this regard, certain dimensional and performance characteristics become important. In particular, closures of this nature are typically applied to associated containers by high-speed, automatic capping equipment, including capping heads or chucks which rotatably fit each internally threaded closure to an associated, externally threaded container. Closures configured for tamper-indication typically include a tamper-indicating pilfer band depending from a skirt portion of the closure, which pilfer band is configured for cooperative engagement with the associated container so that the pilfer band is either partially or completely separated from the remainder of the skirt portion during initial removal of the closure from the container.
As will be appreciated, it is important that closure pilfer band remain intact attendant to high-speed application to an associated container, notwithstanding the inevitable interfering engagement of the closure pilfer band with portions of the container, such as its external thread formation, attendant to initial closure application. During typical closure application, closures are applied to bottles or other containers by rotation, until the closure/container thread interactions draw the closure down against the closure sealing feature, which contacts the upper extreme rim of the container finish.
One type of closure tamper-indicating pilfer band includes a substantially continuous ring which extends generally upwardly and inwardly into the interior of the closure. Closures of this nature can exhibit some problems attendant to high-speed application. In particular, if there is too much interference around the entire ring with the so-called “A diameter” of the container, at the relatively enlarged annular container locking ring, the closure will be difficult to apply without folding the pilfer band ring up into the closure. On balance, if there is insufficient interference, there is a chance that the tamper-indicating function of the pilfer band can be impaired by the ring becoming wedged between the band portion of the pilfer band, and the A-diameter of the container during removal of the closure.
The present invention contemplates an improved configuration of a pilfer band for a tamper-indicating closure which enhances engagement with an associating container, but desirably avoids the addition of too much weight to the closure, and further desirably avoids creating too much resistance and hoop stress as the pilfer band moves over the container finish during closure or application.